The present invention relates to a carbonaceous ferromagnetic material and a method for the preparation thereof. More particularly, the invention relates to a ferromagnetic material consisting substantially of carbon alone without containing any metallic or, in particular, transition metal elements as well as a method for the preparation thereof.
As is well known, conventional ferromagnetic materials are formed from a metal, alloy or oxide of certain ferromagnetic transition metal elements such as iron, cobalt, nickel and the like. These ferromagnetic materials advantageously have a large magnetic susceptibility as well as large coercive force and residual magnetization. Along with these advantageous properties, however, these conventional ferromagnetic materials have several disadvantages and problems. For example, (1) these ferromagnetic materials usually have a large specific gravity because the principal ingredients in the ferromagnetic material are heavy metal elements so that the application thereof is limited not to be suitable for mounting, for example, on spacecrafts, (2) the natural resources of the transition metals, excepting iron, are limited in the geological occurrence so that exhaustion of the resources will be a serious future problem, (3) as an inherent property in metallic and ceramic materials, these ferromagnetic materials have high hardness and rigidity to cause some problems and difficulties in the mechanical working thereof as compared with soft or flexible materials, (4) a large energy is required for the demagnetization of these ferromagnetic materials in a magnetized state so that, when they are to be discarded as a waste material, an economical problem must be taken into consideration because ferromagnetic materials discarded before demagnetization sometimes cause a serious environmental problem, (5) some of the heavy metal constituents in these ferromagnetic materials have toxicity against and low adaptability to living bodies so that their application to living bodies is limited in this regard, and so on.